You need to save up and do a stage 3 power pack...their products are tried and true http://www.supersixmotorsports.com/pdf/SSM2010catrev1PowerPaks.pdf
It would get you from 200 to 290hp... so almost as much as a stock 5.4. Not sure which would be cheaper
I'll just buy a 4x4 with the 5.4 in it for not much more than that. Still a great find. But theres no way im paying that much.